Found 10456 publications. Showing page 412 of 419:
Boreal forests at risk: Absence of climate perspectives in current management policies
Boreal forests influence climate both biogeochemically through carbon uptake and biogeophysically through evapotranspiration, turbulent fluxes and albedo, and are in turn impacted by climate through biotic and abiotic damages. This systematic literature review and qualitative narrative policy review and analysis aims to get a better insight into the discrepancy between policy and science on forestry action to mitigate climate warming in high latitude jurisdictions. We identify climate effects on and from forests with corresponding management options in a systematic review of scientific literature following PRISMA guidelines. These results were combined with a qualitative policy review and analysis to identify the climate and forestry policies from all boreal-to-Arctic jurisdictions and determine how (many of) these climate effects ended up in forest and climate policy. There is mounting evidence that in boreal regions, albedo-driven warming can partially offset, and in some contexts be comparable to, carbon-driven cooling; the balance varies by season, forest type and disturbance history. However, although all analysed jurisdictions (Alaska, Canada, European Union, Sweden, Finland, Iceland, Norway and Russia) recognise the forests' role in carbon uptake, none recognise the albedo effect, and none translate these climate effect into binding regulatory measures. Nor do most of the jurisdictions take into account possible risk of climate-related damages. This might lead to ineffective and even adverse forest and climate measures. Our study emphasises a need for more evidence-based and comprehensive climate and forestry policies and regulations, along with a proactive approach to adopting these measures swiftly.
2026
Coastal aerosols are formed through the complex mixing between marine air masses and continental emissions, which originate from both natural and anthropogenic sources. The properties of coastal aerosols are decisive for their interaction with sunlight and their influence on clouds, as well as the potential health implications for the population in these areas. In this study, the aerosol properties and sources at Aarhus Bay, Denmark, were investigated by combining in situ aerosol light scattering and absorption with size distribution measurements and footprint analysis by FLEXPART. Our analysis demonstrates a considerable contribution of anthropogenic aerosols from both fossil fuel combustion and biomass burning, as well as periods with highly scattering aerosols. Furthermore, good agreement was found between in situ and modelled black-carbon data. Combining in situ measurements and FLEXPART analysis further evidenced a major impact of local emissions, as well as a few long-range transport intrusions.
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2026
Biogenic volatile organic compound (BVOC) emissions from vegetation represent a major source of volatile compounds globally and play an important role as precursors for tropospheric ozone. Understanding their emissions is therefore crucial for quantifying the impact of ozone on air quality. We present two datasets of biogenic volatile organic compound emissions that cover the European modelling domain of the Copernicus Atmospheric Monitoring Service at a resolution of 0.1° × 0.1° to support the study of European scale air quality. The compounds included in the dataset follow the VOCs included in the regional atmospheric chemistry model mechanism (RACM). The datasets were produced within the framework of the EU's SEEDS project. We produced each dataset by coupling modelling output variables from the SURFEX land surface model with the MEGAN3.0 BVOC emission model. In one instance, the SURFEX model was run in free-running mode, which we term the open-loop (OL) and in the other case we assimilated satellite observations of leaf area index (LAI), which we term the analysis. The OL and analysis land surface model outputs form the basis for each emission dataset that are called SURFEX-MEGAN3.0 OL (https://doi.org/10.7910/DVN/LAUVTU, Hamer et al., 2025a) and SURFEX-MEGAN3.0 analysis (https://doi.org/10.7910/DVN/69G1FX, Hamer et al., 2025b), respectively. The OL dataset is available over a five-year period from 2018–2022 and the analysis dataset is available over the three-year period 2018–2020. SURFEX was run for both the OL and analysis simulations in a configuration that allowed simulated vegetation to respond to variations in meteorology over time to more realistically track vegetation phenology. Evaluation of the land surface model output LAI and root-zone soil moisture (RZSM) showed that the OL and analysis simulations had good skill at tracking temporal changes in both variables, with the analysis performing better in each instance. We perform a variety of evaluations on the isoprene emissions specifically given the importance of this compound for atmospheric chemistry. We evaluated the temporal variability of isoprene emissions in both datasets and found that the majority of the interannual and monthly variability was linked to variability in LAI that in specific cases, like the summer of 2019, could be linked to drought impacts on vegetation growth simulated by SURFEX. We evaluated the daily temporal variability of the OL and analysis isoprene emission datasets against in-situ online observations of isoprene concentrations at 8 sites in western Europe and found moderate to strong correlation between the emissions and observations in almost all location-year pairings. We also evaluated the OL and analysis emission datasets against other published bottom-up isoprene emission datasets over the same European domain used in this study. We found that the SURFEX-MEGAN3.0 OL and analysis isoprene emission datasets lie between the minimum (CAMS-GLOB-BIOv3.1) and maximum (MEGAN-MACC) published emission datasets based on bottom-up approaches. Furthermore, we were able to attribute differences in seasonality between SURFEX-MEGAN3.0 and other emission inventories to differences in the temporal variability of the underlying LAI dataset used to compile them. Overall, our findings show the importance of variability in LAI in controlling isoprene emissions on monthly to annual timescales. Combining this with the demonstrated skill of the emissions in evaluation with independent data, this points towards the value of an Earth-system approach to BVOC emission modelling.
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Exceptional high AOD over Svalbard in summer 2019: a multi-instrumental approach
In the summer of 2019, the Arctic region registered exceptionally high aerosol optical depth (AOD) values over Svalbard, linked to intense biomass burning (BB) and volcanic activity across the Northern Hemisphere. This study presents a comprehensive, multi-instrumental analysis of the aerosol conditions in and around Ny-Ålesund (Spitsbergen, Norway), combining data from ground-based sun-photometry, in-situ observations, active remote sensing (ground-based and on satellite), and atmospheric dispersion modelling (FLEXPART). Despite high AOD was observed during all the period, three different aerosol events are identified in the atmospheric column (6–10 July, 25–28 July, and 6–17 August). In contrast, in-situ surface stations only recorded significant aerosol load during 5–9 July, 30 August, and 12 September, suggesting that most of the aerosol particles remained above the boundary layer. Lidar and photometric observations revealed the presence of spherical, weakly absorbing Accumulation-mode particles (with effective radii between 0.1 and 0.2 µm) in both the troposphere and stratosphere, with persistent layers extending above 10 km. Simulations carried out with FLEXPART correlate well with the measurements, attributing the observed aerosol events to multiple sources, including Siberian and North American wildfires, the Raikoke (Russia) volcanic eruption, and anthropogenic pollution. While the simulations show a contribution from volcanic aerosols, the contribution from biomass-burning aerosols in the upper troposphere and lower stratosphere were likely more significant under the atmospheric conditions of summer 2019. Overall, the aerosol radiative impact during this long-lasting event was substantial, with a mean reduction in direct solar radiation of approximately −74 W m−2 during July and August. This work shows how the use of dispersion modelling together with multiple observation sources allows to achieve a more complete description of the atmospheric aerosol events and contributes to a better understanding of the overall picture.
2026
Biogenic volatile organic compound (BVOC) emissions from European vegetation are a major precursor of tropospheric ozone and remain a key uncertainty in regional air-quality modelling. We present two high-resolution (0.1° × 0.1°) European BVOC emission datasets developed within the EU SEEDS project aimed at supporting scientific development within Copernicus Atmospheric Monitoring Service (CAMS). The datasets include BVOC species consistent with the RACM chemical mechanism and are generated by coupling the SURFEX land surface model with the MEGAN3.0 emission model.Emissions based on two land surface model simulations were analysed: (i) an open-loop SURFEX simulation available for 2018–2022, and (ii) a data-assimilation simulation in which satellite leaf area index (LAI) observations are assimilated, available for 2018–2020. In both cases, SURFEX is configured to allow vegetation phenological responses to meteorological variability, enabling a realistic representation of phenology. Evaluation against independent datasets shows that both simulations capture temporal variability in LAI and root-zone soil moisture, with improved skill in the analysis configuration.Given its importance for atmospheric chemistry, we focus on isoprene emissions. Interannual and seasonal variability in isoprene emissions is shown to be primarily driven by LAI variability, with specific events (e.g. summer 2019) linked to drought-induced vegetation stress simulated by SURFEX. Daily variability in isoprene emissions is evaluated against in-situ online isoprene concentration measurements at eight western European sites, revealing moderate to strong correlations across most site-year combinations. Comparisons with other bottom-up European isoprene inventories show that SURFEX-MEGAN3.0 emissions lie between the lower CAMS-GLOB-BIOv3.1 and higher MEGAN-MACC estimates, with differences in seasonality attributable largely to the underlying LAI datasets.These results highlight the important role of vegetation phenology, particularly LAI variability, in controlling BVOC emissions on monthly to interannual timescales, and demonstrate the added value of an Earth-system approach for BVOC emission modelling in support of air-quality assessments.ReferencesHamer, . D., Markelj, M., Rojas-Munoz, O., Bonan, B., Calvet, J.-C., Marécal, V., Guenther, A., Trimmel, H., Vallejo, I., Eckhardt, S., Sousa Santos, G., Sindelarova, K., Simpson, D., Schmidbauer, N., and Tarrasón, L.: Two Biogenic Volatile Organic Compound Emission Datasets over Europe Based on Land Surface Modelling and Satellite Data Assimilation, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2025-442, in review, 2025.
2026
Siri (14) gjør en viktig jobb for forskningen i Norge
Hver uke sender Siri Leifsen vannprøver til forskningsinstituttet NILU for analyse av ulike stoffer i nedbør. Tenåringen bidrar til forskning på miljøovervåkning.
2026
This study provides a short-term, dry-weather multi-compartment assessment of microplastic (MP) contamination in the Choghakhor Wetland, a vital freshwater ecosystem in western Iran. We quantified MPs in air, subsurface water, the surface water microlayer (SML), and sediments and developed a first-order mass-balance framework to clarify transport and fate. The SML showed much higher MP concentrations than the subsurface water when converted to volumetric units, while method-specific SML estimates varied among approaches (4.4–13.8 MP m⁻² using a glass tube; 196–982 MP m⁻² using a sieve; and 130–1754 MP m⁻² using filter paper). Subsurface water contained 0.083–1.5 MP L⁻¹, and the two sediment samples contained 60–400 MP kg⁻¹. Atmospheric deposition during the monitored intervals reached 2363 MP m⁻² h⁻¹. Flux analysis indicated that dry-weather influx exceeded observed outflux by more than three orders of magnitude. Using the conservative combined-outlet scenario, the wetland residence time was at least 168 days, whereas a water-only outlet scenario yielded ∼344 days. FLEXPART suggested that road dust dominated modeled source contributions, with smaller agricultural and soil-related contributions, although site-specific attribution remains model-based. These findings identify wetlands as important sinks and reservoirs of MPs, while emphasizing that the present results represent a dry-weather baseline rather than seasonal or annual conditions.
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Long-term trend of elemental carbon in the high Arctic and its potential drivers
The Arctic is warming at more than twice the global average rate, a phenomenon known as Arctic amplification (Rantanen et al., 2022). In addition to greenhouse gases, short-lived climate forcers play a critical role in modulating Arctic climate through their impacts on radiation, cloud properties, and the surface energy balance (e.g. AMAP, 2015, 2021). Among these forcers, elemental carbon (EC) is of particular importance due to its strong light-absorbing properties and its ability to reduce surface albedo when deposited on snow and ice. Furthermore, aged EC particles transported to the Arctic can act as cloud condensation nuclei, influencing cloud microphysical processes and thereby modifying Arctic radiative forcing and climate feedbacks.In this study, we investigate long-term trends in EC concentrations and their potential drivers in the high Arctic using 16 years of continuous EC measurements from the Villum Research Station in northeast Greenland. We combine in situ observations with Lagrangian transport modelling and back-trajectory analyses to assess the relative contributions of changes in source-region emissions, transport pathway variability, and wet scavenging processes to the observed EC trends. Robust non-parametric statistical methods are applied to assess monotonic trends over the full observational period and before 2020, enabling a systematic comparison between the declining and stagnating phases. This integrated observational–modelling framework provides new constraints on the processes controlling EC variability in the Arctic and advances our understanding of how anthropogenic emission reductions are reflected in Arctic atmospheric composition under a rapidly evolving climate.
2026
Plastic pollution is an ever-growing concern around the globe, with current research portraying the presence of contaminants even in previously pristine regions. Especially small particles, micro- and nanoplastics, can be dispersed over long stretches by atmospheric transport, reaching even the most remote areas of the planet. This study aims to portray current levels of nanoplastic contamination (< 1 μm) by analyzing snow samples from high-altitude glaciers in the European Alps (2300–3800 m) via TD-PTR-MS. We were able to detect six common plastic pollutants, with PE and PP contributing over 60% of the total mass concentration measured across all sites. On average, nanoplastic concentrations of 85 ng mL − 1 (range: 3.6 ± 12 ng mL − 1 – 470 ± 76 ng mL − 1 ) were detected at sampled glacier surfaces. Access to these remote regions was enabled through a citizen-science initiative, involving trained mountaineers for sample collection. The results were applied to atmospheric modelling, highlighting possible point sources of contamination. While agriculture and local plastic factories were revealed as potential sources of nanoplastics, spatial and temporal limitations complicated comparison inside the sample cluster.
2026
Microplastic and other anthropogenic particles in surface waters of the Isfjorden system (Svalbard)
Knowledge of sources and transport mechanisms of anthropogenic particles (APs) such as microplastics (MPs) and related plastic chemicals, in the Arctic marine environment is limited. This study investigates the surface waters of the Isfjordensystem, where Svalbard's largest settlement, Longyearbyen, is located, for the presence of APs. The wastewater from Longyearbyen is released untreated into Adventfjorden, which is a branch of Isfjorden. Samples from the inflowing current of Isfjorden into Adventfjorden, and its outflowing current were sampled and analyzed for APs (>50 μm). APs were classified regarding size, shape, and polymer type via μFTIR spectroscopy. Each location showed an AP burden (Isfjorden: 26 APs/L, Adventfjorden: 20 APs/L). Highest amounts of APs were found in the Isfjorden current (37 APs/L), before entering Adventfjorden. 14 APs/L were indicated near the wastewater effluent in Adventfjorden, and 15 APs/L in the outflowing current in Isfjorden. Plastic related chemicals, polypropylene and other polyolefins had high frequencies, but silk and rayon material dominated each location except the inflowing current from Isfjorden. Local sources like wastewater and other anthropogenic activities, as well as northwards long-range transport from the south into the Arctic, are considered. Oceanographic dynamics, and the time of sampling seems to affect the distribution of APs in the surface waters, besides its characteristics itself (e.g., polymer type and size).
2026
Gastrointestinal image classification with GIDNet CNN model and non-linear Tansh activation function
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